The objective of this project is the development and laboratory testing of a convenient technique for sampling trace compounds in exhaled air. Breath analysis has several theoretical advantages over other methods of monitoring worker exposure to industrial solvents, but its utilization has been hindered by unreliable or impractical sampling technology. The method proposed here is based on an air purifying respirator, to which is added a sampling cartridge in the exhaled air port. Thus, a worker under examination would inhale contaminant-free air, but his exhaled air would pass successively through layers of activated charcoal cloth and a bed of dessicant. Any solvent vapor in exhaled air, reflecting absorption into the bloodstream, will be collected on the charcoal cloth, which will then be removed and analyzed. The weight gain of the dessicant will provide a measure of the volume of exhaled air sampled. The system will be thoroughly tested with several organic solvents using a controlled-atmosphere chamber. The concentrations used will extend into the parts per billion range, representing a major improvement in sensitivity over previous methods.